Belt printer

ABSTRACT

An impact mechanism prints directly on the outer coil of a web of paper using the web itself as a backing thereby obviating the use of a separate platen. In order to hold the outer coil in a printing plane, a pair of springs continuously urge the web against a pair of stops which are adjacent to the impact mechanism. The impact mechanism includes a plurality of tines which are positioned to strike character dies against the web upon being struck by pins. The pins are distributed in a single turn helix about a cylinder which is rotatably mounted on a pivoted bracket. The cylinder rotates to index the pins across the tines and reciprocates to strike the pins against the tines. In order to sever the web into sheets after information has been recorded thereon, a pair of rollers are positioned to grip the paper being advanced from the web so that the paper may be manually brought into contact with and severed by a fixed blade.

United States Patent [1 Metz [ 1 Oct. 28, 1975 [44] Published under theTrial Voluntary Protest Program on January 28, 1975 as document no.

[75] Inventor:

[52] US. Cl 197/1 R; 197/53; 197/144;

l0l/93.l4; 101/228 [51] Int. C1. B41J 3/44 [58] Field of Search 197/1,144, 133, 53;

[56] References Cited UNITED STATES PATENTS 765,532 7/1904 White 10l/9 3C X 1,191,697 7/1916 Himmer 101/228 2,152,031 3/1939 Currier 225/852,918,865 12/1959 Wooding.... 101/93 C 3,113,509 12/1963 Simpson 101/1113,651,915 3/1972 Folkens 197/53 I 3,698,529 10/1972 Cattaned 101/93 C XPrimary ExaminerRobert E. Pulfrey Assistant ExaminerR. T. RaderAttorney, Agent, or Firm-J. L. Landis [5 7 ABSTRACT An impact mechanismprints directly on the outer coil of a web of paper using the web itselfas a backing thereby obviating the use of a separate platen. In order tohold the outer coil in a printing plane, a pair of springs continuouslyurge the web against a pair of stops which are adjacent to the impactmechanism. The impact mechanism includes a plurality of tines which arepositioned to strike character dies against the web upon being struck bypins. The pins are distributed in a single turn helix about a cylinderwhich is rotatably mounted on a pivoted bracket. The cylinder rotates toindex the pins across the tines and reciprocates to strike the pinsagainst the tines. In order to sever the web into sheets afterinformation has been recorded thereon, a pair of rollers are positionedto grip the paper being advanced from the web so that the paper may bemanually brought into contact with and severed by a fixed blade.

12 Claims, 3 Drawing Figures US. Patent Oct. 28, 1975 BELT PRINTERBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to printers and more particularly to impact printers whichrecord information on material fed from a roll or web.

2. Technical Considerations and Prior Art Printers tend to be verycomplicated mechanisms with many moving parts. Generally, the cost ofpurchase and maintenance of a printer is directly proportional to itscomplexity. Consequently, a reduction in complexity is a necessary stepin producing printers for the low cost market.

One of the more complicated mechanisms necessary in a printer is someagency for selectively moving the characters to be printed across thepage. In recent years, much attention has been directed to belt or chainprinters exemplified by the teachings in US. Pat. No. 2,918,865, whichissued to E. R. Wooding, in which the characters are distributed in theform of dies along an endless carrier. However, until recently, the highcost of logic circuits for positioning the characters across a page hascurtailed utilization. Improvements in microminiature circuit technologyhave resulted in cost reductions that now render belt printerscommercially feasible for the low cost market.

As a result of these improvements, there is now an opportunity tosimplify belt printers by reducing the complexity of the othermechanisms such as impact mechanisms and paper cutters associatedtherewith. In prior art printers, a platen or other type of backstop isutilized as a backing for the paper to support the paper in a printingplane as an impact mechanism strikes characters onto the paper. In orderto properly align and tension the paper as it advances from a supply tothe platen, additional devices such as guides and feed rollers arenecessary. One way to reduce the number of parts and thus simplify theprinter is to dispense with the platen or backstop and print directly ona roll or web of paper, which is what is done in the instant invention.

If one is going to print directly on the web of paper, then a suitableimpact mechanism must be utilized. The impact mechanisms of the priorart belt printers, such as that shown in the aforementioned US. Pat. No.2,918,865 to E. R. Wooding, cannot be used with a printer which printsdirectly on a web of paper because such mechanisms have hammers and typemembers positioned on both sides of the printing plane with the typemembers serving essentially as platens which support the paper.Consequently, an impact mechanism which can operate from only one sideof the paper must be used.

In the instant invention, an impact mechanism located entirely on oneside of the printing plane is created by spacing a series of pins or thelike about a cylinder to form a single-tum helix. The pins are seriallymoved to printing modes along the paper by rotatably indexing thecylinder. After each index, the cylinder is then reciprocated to impactthe pins against resilient tines which, in turn, strike dies to printcharacters on the paper. There are disclosures in the prior art ofmodern printers with helically disposed ribs, pins and the like;however, these helical arrangements are used generally as backingsagainst which other hammers print rather than as hammers themselves.Furthermore, the

prior art does not disclose using resilient tines to transfer the impactfrom the helically disposed elements to the printing dies.

Since the paper is fed from a roll, it is necessary for the sake ofconvenience to sever the paper into sheets as each complete message isrecorded. In the prior art, stationary blades are generally used but nomechanism for adequately gripping the paper is disclosed. Since thepresent invention prints directly on the web of paper, there are nointermediate devices such as guides or feed rolls to bind or retain thepaper when it is manually engaged with the blade for cutting.Consequently, it is quite possible to unwind unnecessary amounts ofpaper from the web upon trying to sever the paper into sheets. In thepresent invention, rollers are provided to grip the paper upon applyinga horizontal force to the paper so as to avoid transferring the pullingforce back to the web.

SUMMARY OF THE INVENTION In light of the aforementioned considerations,it is therefore an object of this invention to provide a new andimproved printer which prints directly on a web of material utilizingthe underlayers of the material and the tiller roll of the web as abacking.

It is a further object of this invention to provide a new and improvedimpact mechanism which may be used with printers that print directly ona web of material.

It is still a further object of this invention to provide a new cuttingapparatus for severing material in sheets after it has been printed uponwherein the cutting apparatus is suitable for use with a printer thatprints directly on a web of material.

In accordance with these and other objects, the invention contemplatesmounting a web of paper so that it is continuously urged into a printingplane in which an impact mechanism serially distributes informationacross the outer coil of the web using the web itself as a backing. Theimpact mechanism includes a line of spaced projections helicallydistributed around a cylinder. The cylinder is rotatably mounted on apivoted bracket and uses a ratchet mechanism to index the projectionsinto a printing mode each time the bracket piv- OtS.

As the bracket pivots, it causes the projections to strike serially thefree ends of resilient tines which, in turn, strike character diesmounted on a selectively movable belt. The character dies print directlyon the web of paper as they are struck. As each message is recorded, thepaper from the web is severed into sheets by a fixed blade. In order toprevent advancement of the paper as it is severed, a pair of rollers areprovided to grip the paper therebetween upon manually pulling the paperin the horizontal direction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of aprinter embodying the principles of the present invention wherein theprinter prints directly on the outer coil of a web of paper and whereinthe printer utilizes a rotatable cylinder with a helical arrangement ofpins to strike tines of a resilient comb in order to impact type diesagainst the outer coil of the web;

FIG. 2 is an enlarged side view taken along line 22 of FIG. 1, showing aratchet and detent mechanism for rotating and positioning the cylinderupon which the pins are helically distributed; and

FIG. 3 is a side view of a device used with the printer of FIG. 1 forsevering .the paper from the web into sheets wherein the paper isgripped by a pair of rollers and severed by a cutting blade.

DETAILED DESCRIPTION Referring now to FIG. 1, there is partiallyillustrated a printer designated generally by the numeral 9, whichsupports a web of a carrier such as paper shown coiled around a filler11 and mounted for rotation on a nonrotatable spindle 12 by a bearing13. The web 10 and filler l I serve as a backing against which an impactmechanism, designated generally by the numeral 14, impacts as it printscharacters with belt-supported dies 15 on the outer coil 16 of the web.The spindle 12 has a recess 17 formed in each end thereof, (only one ofwhich is shown) in which is seated a spring 18 that biases the entireweb '10 toward the impact mechanism 14.

Each spring 18 rests upon a platform 21 which is, in turn, positioned ona set of pins 22 that pass through bores 23 in its platform. The pins 22in each set are rigidly secured to a frame 24 which supports the entireprinter 9, including the impact mechanism 14. In order to adjust thecompression and thus the force of each spring 18, an adjustment screw 25(only one of which is shown) is threaded in the frame 24 and abuts thelower surface of the corresponding platform 21. It is to be understoodthat the structure supporting the hidden right end of the spindle 12 isidentical to the structure supporting the visible left end of thespindle.

The springs 18 urge the web of paper 10 against a pair of spaced,parallel rollers 26 which are rotatably secured to the frame 24 anddefine the printing plane of the printer 9. The bias of the springs 18slightly compresses the web of paper 10 to ensure a firm printingsurface on which the impact mechanism 14 can record.

Positioned between the rollers 26 is a printing belt 27 which carriesthe character dies 15. The printing belt 27 is trained positively aboutand supported by an idler pulley 28 and a drive pulley 29. The drivepulley 29 is driven by a drive motor 31 that is controlled from a mastercontroller 32 to position the character dies 15 in selected sequentiallocations across the web 10. The master controller 32 can be of the typedisclosed in U.S. Pat. No. 2,918,865 which issued to E. R. Wooding. Aconventional inked ribbon 33, supported by supply and take-up spools 34and 35, is disposed between the printing belt 27 and the outer coil 16of the web 10 to render impacts by the dies 15 visible.

Positioned above the belt 27 and between the rollers 26-26 are aplurality of pallets 37, each of which corresponds to a printing spacein a line of print across the outer coil 16 of the web of paper 10. Thepallets 37 are, in turn, each secured to the free end of a separate oneof a plurality of tines 38. The tines 38 are formed in a sheet of springsteel, or the like, to form a comb 39, the butt 45 of which is rigidlysecured to the frame 24 of the printer.

In order to impact the pallets 37 against the dies 15, a series ofspaced pins 40 are arranged in a single turn helix about the outersurface of a cylinder 41. The cylinder 41 is mounted on its longitudinalaxis to a pair of flanges 42 in a steel bracket 43 and can rotate toposition sequentially each pin 40 in a printing mode over an associatedpallet 37. Consequently, as the cylinder 41 rotates, the pins 40 areprogressively located over the line of pallets 37 in position to print aline of type across the outer coil 16 of the paper web 10.

The bracket 43 is mounted by pivots 44 to the frame 24 of the printer 9.As the bracket 43 pivots, it moves the cylinder 41 normal to itslongitudinal axis carrying the pins 40 toward and away from the pallets37. The bracket 43 has a tab 46 projecting therefrom to which one end ofa contractile spring 47 is attached. The other end of the spring 47 isattached to a projection 48 on the frame 24 so that the spring urges thebracket 43 in a clockwise direction about pivots 44 thereby moving thecylinder 41 and the pins 40 away from the pallets 37.

In order to cause the pins 40 to impact against the pallets 37, anelectromagnet 49 is positioned beneath the bracket 43 to attract thebracket and rotate it counterclockwise, against the biasing action ofthe spring 47, upon receiving a print signal from the controller 32. Asthe bracket 43 is rotated counterclockwise, it causes a pin 40vertically posed for printing to strike the associated pallet 37.Immediately following this impact, the electromagnet 49 is de-energizedby the controller 32 and the spring 47 returns the bracket 43 to itsinitial position. A stop 52 engages the frame 24 to limit clockwisemovement of the bracket 43.

Referring now to FIG. 2, ratchet and detent mechanisms are illustratedfor rotatively positioning the cylinder 41. It is noted that thesemechanisms were not illustrated in FIG. 1 for purposes of clarity. Aratchet pawl 53 engages a ratchet wheel 54 which is rigidly secured tothe cylinder 41 for rotation therewith. The ratchet pawl 53 is mountedto the frame 24 for pivotal movement about a pin 56 and is urged intoengagement with the ratchet wheel 54 by a spring 57. When the bracket 43is moved in a clockwise direction about the pivots 44 under the urgingof the spring 47, the cylinder 41 and the ratchet wheel 54 are raised.The interaction between the ratchet pawl 53 and the raising ratchetwheel 54 causes the wheel and the cylinder 41 to be rotated in aclockwise direction.

In order to properly position the cylinder 41, a detent 58 is pivoted ona pin 59 mounted on the bracket 43 and is urged into engagement with oneof a plurality of indents 61 in the cylinder 41 by a compression spring60. Each indent 61 corresponds in circumferential location to one of thepins 40 and thereby corresponds to one space in the line to be printedon the web 10. Consequently, as the cylinder 41 is rotated, the detent58 is permitted to move out of the indent 61. This permits the cylinder41 to be moved through a sequence of positions which locate the pins 40in succession over their respective pallets 37 in succession forprinting.

The ratchet and detent mechanism operates as follows. As the spring 47urges the bracket 43 clockwise, the ratchet wheel 54 is raised and thepawl 53 engages a tooth of the ratchet wheel causing the cylinder 41 torotate clockwise until the stop 52 engages the frame 24 to preventfurther rotation. At this time, the detent 58 engages the nextsuccessive indent 61 preventing further rotation of the cylinder 41.

Upon energizing the electromagnet 49, the bracket 43 rotates in thecounterclockwise direction about pivots 44 moving the cylinder 41 normalto the cylinders longitudinal axis and toward the pallets 37. Since thedetent 58 is engaged with one of the indents 61, the cylinder 41 willnot rotate and the ratchet pawl 53 will be cammed out of engagement withthe teeth of the ratchet wheel 54. Oneof the pins 40 will be alignedwith one of the pallets 37 and will strike that pallet as the bracket 43rotates. After the pin 40 strikes the pa]- let 37, the electromagnet 49is de-energized and the bracket 43 again rotates clockwise under theinfluence of the spring 47 causing the ratchet pawl 53 to rotate theratchet wheel 54 and cylinder 41 as before.

Referring again to FIG. 1, after each line is printed, a control signalis generated by the controller 32 to a paper advance motor 62,instructing the motor to rotate a resilient roller 63 in acounterclockwise direction. The section 65 of paper extending away fromthe outer coil 16 of the web is urged by a second resilient roller 64against the roller 63. This of course advances the extended section 65of paper by pulling it from the web 10 and causing the web to uncoil andposition fresh paper in the printing plane.

Selected lengths of the section 65 may be severed from the outer coil 16by a paper cutting portion of the printer, designated generally by thenumeral 70 and illustrated in FIG. 3. The paper cutter is locateddownstream of the resilient rollers 63 and 64, comprising the paperadvance mechanism. In the paper cutter 70, the section 65 of the paperis advanced between a pair of light weight rollers 66 and 67 which havehigh friction surfaces 68 and 69, respectively, of rubber or the like,located thereon for engaging the paper. The rollers 66 and 67 aremounted by pins 71 and 72, respectively, in slots 73 and 74,respectively, formed in the frame 24. The slots 73 and 74 convergetoward the downstream end of the section 65 of the paper so thatordinarily the upper roller 66 rests upon the section 65 lightlypressing the paper against the lower roller 67.

While the section 65 of the paper is being advanced, it is pushed by thepaper advance motor 62 between the rollers 66 and 67, causing them torotate in opposite directions due to friction between the surfaces 68and 69 and the paper. As the paper emerges from between the rollers 66and 67, it falls downwardly in the direction of arrow 76. When it isdesired to sever the leading portion of the section 65 of the paper, thepaper is manually gripped and pulled in the horizontal direction asindicated by the dotted line. This causes the pins 71 and 72 to movedownstream in the slots 73 and 74, and thus move rollers 66 and 67slightly toward one another thereby securely gripping the section 65 ofthe paper disposed therebetween. Upon lifting the leading portion of thesection 65 slightly upward, it engages a fixed blade 77 extending acrossits width which neatly cuts the paper as the paper is pulled against theblade in the direction of arrow 78. After a sheet of the paper 10 issevered, the portion just upstream of the blade 77 falls away in thedirection of arrow 76. Since there is no horizontal tension on thepaper, the rollers 66 and 67 will cease to be urged tightly together andtherefore will cease to grip the paper. The paper will then advancefreely between the rollers 66 and 67 as the paper advance motor 62(FIG. 1) pushes it.

To summarize the operation of the printer disclosed in the preferredembodiment, the controller 32 receives a print signal whereupon itpositions a selected character die beneath the first pallet 37 which islocated at the left end of the comb 39. The controller 32 then energizesthe electromagnet 49 and the first pin 40 strikes the first pallet 37printing the first desired character into the first space on theprepositioned outer coil 16 of the paper. The controller 32 thende-energizes the electromagnet 49 and the bracket 43 rotates clockwisethereby rotating the cylinder 41 one space with the ratchet and detentarrangement shown in FIG. 2 to position the next successive pin 40 overthe second pallet 37.

The controller 32 then signals the drive motor 31 to position the seconddesired character die 15 beneath the second pallet 37 and energizes theelectromagnet 49. The electromagnet 49 is again energized to print thesecond character into the second space on the outer coil 16 of thepaper. The process continues until an entire line of print is recorded.If a blank space is desired, blank areas are provided on the printingbelt 27 so that nothing will be recorded when the pin 40, which is inposition for recording, strikes its associated pallet 37. After eachline of print is recorded, the controller 32 signals the paper advancemotor 62 to advance the paper one or more spaces. A new line is nowready for printing after the complete message is recorded.

I claim:

1. In an apparatus for recording characters selectively and sequentiallyacross an outer coil of material as the material is uncoiled from a webof the material;

an impact mechanism for striking character dies against the material;

means for continuously urging the web and the impact mechanismrelatively toward each other to permit the uncoiled portion of the webto serve as a backing for the outer coil of material against which thecharacter dies strike when the characters are recorded; and

means positioned between the web and the impact mechanism for engagingthe outer coil of material of the web and for holding successivesections of the outer coil in a printing location relative to the impactmechanism and against the web as the web uncoils.

2. The apparatus of claim 1 wherein the means for urging the webcomprises a spindle upon which the web is mounted and a pair of springsengaging each end of the spindle to urge the spindle toward the impactmechanism.

3. The apparatus of claim 1 wherein the impact mechanism includes:

a cylinder mounted for rotation about its longitudinal axis;

means for reciprocating the cylinder selectively normal to thelongitudinal axis;

means for rotating the cylinder about said axis through a predeterminedarc upon each reciprocation of the cylinder, and

means for impacting the characters against the material to record thecharacters thereon upon each reciprocation of the cylinder, wherein saidimpacting means is distributed around said cylinder in a helical patternto print the characters across the sheet of material as the cylinderreciprocates and rotates.

4. The apparatus of claim 3 wherein the characters are mounted on amovable carrier positioned between the material and the cylinder.

5. The apparatus of claim 3 further including a plurality of resilienttines aligned with preselected spaces on the material and having palletportions thereon for printing the characters upon being struck by saidimpactmg means.

6. The apparatus of claim wherein the impacting means comprises aplurality of spaced pins arranged in a single turn helix about thecylinder and wherein the pins are sequentially aligned with individualtines as the cylinder rotates.

7. In an apparatus for printing individual sheets of information whereinthe sheets are produced sequentially from the outermost coil of a web ofmaterial;

an impact mechanism for printing information on the outermost coil ofthe web;

means for continuously urging the web toward the impact mechanism sothat the remainder of the web serves as a backing for the outer coil ofthe web against which the impact mechanism strikes when printing;

means independent of the impact mechanism for engaging and holding theoutermost coil of the web in a printing plane relative to the impactmechanism and against the web as the outermost coil is printed on; and

means for severing sheets from the web.

8. The apparatus of claim 7 wherein said severing means includes:

a pair of rollers between which material from the web advances;

means for mounting the rollers to selectively prevent the advancement ofthe material; and

a blade positioned downstream of the rollers to sever a sheet from thematerial upon engaging the material.

9. The apparatus of claim 8 wherein the means for mounting the rollersincludes pins projecting from each end of each roller wherein the pinsengage slots which converge in a direction downstream of the web.

10. In an apparatus for recording characters selectively andsequentially across an outer coil of material as the material isuncoiled from a web;

means for continuously urging the web into a printing plane to positionthe outer coil for a printing operation;

dies for printing the characters on the web;

a carrier for moving the dies selectively across and adjacent to theprinting plane; 1 a plurality of resilient tines aligned withpreselected spaces in the printing plane but positioned on the oppositeside of the dies wherein said tines have portions thereon for strikingthe dies;

a cylindrical helix juxtaposed with and axially extensive across saidtines;

means for reciprocating said helix normal to its axis to impact saidhelix against said tines causing said tines to strike said dies andrecord the characters on the outer coil of the material;

means for rotating said helix to position said helix to engage saidtines individually and sequentially as said helix is reciprocated; and

means for severing the material after the characters have been recordedthereon, wherein the severing means includes means for restrainingadvancement of the material upon applying a pulling force to thematerial downstream of the severing means to thereby prevent the forcefrom being transmitted back to the coiled web.

11. In an impact printer wherein an impactor means comprises a pluralityof equally spaced apart and outwardly projecting impacting elementsdisposed in a single turn helix on the surface of a cylinder rockablymounted for impacting selected ones of a linear array of characters forprinting, the improvement comprisa carrier for the characters mountedfor transverse movement relative to and along a line on a web on whichprinting is to be effected;

a plurality of resilient tines having an individual pallet attached toeach tine, whereas the pallets are located between the carrier and thecylinder, so that each pallet corresponds to a printing space in a lineof print across the web and is sequentially aligned with successiveimpacting elements as the cylinder rotates for printingly impacting thecharacters; and

magnetic means for rocking the cylinder into element impactingengagement with successive pallets for printing.

12. A combination according to claim 1 1 wherein the tines are disposedin parallel relationship, thereby forming a comb; and the magnetic meanscomprises:

a rockable bracket mounted above the comb, the cylinder rotatablymounted in the bracket; and

a magnet fixed relative to the comb for selectively attracting thebracket to draw the cylinder toward the pallet.

1. In an apparatus for recording characters selectively and sequentially across an outer coil of material as the material is uncoiled from a web of the material; an impact mechanism for striking character dies against the material; means for continuously urging the web and the impact mechanism relatively toward each other to permit the uncoiled portion of the web to serve as a backing for the outer coil of material against which the character dies strike when the characters are recorded; and means positioned between the web and the impact mechanism for engaging the outer coil of material of the web and for holding successive sections of the outer coil in a printing location relative to the impact mechanism and against the web as the web uncoils.
 2. The apparatus of claim 1 wherein the means for urging the web comprises a spindle upon which the web is mounted and a pair of springs engaging each end of the spindle to urge the spindle toward the impact mechanism.
 3. The apparatus of claim 1 wherein the impact mechanism includes: a cylinder mounted for rotation about its longitudinal axis; means for reciprocating the cylinder selectively normal to the longitudinal axis; means for rotating the cylinder about said axis through a predetermined arc upon each reciprocation of the cylinder, and means for impacting the characters against the material to record the characters thereon upon each reciprocation of the cylinder, wherein said impacting means is distributed around said cylinder in a helical pattern to print the characters across the sheet of material as the cylinder reciprocates and rotates.
 4. The apparatus of claim 3 wherein the characters are mounted on a movable carrier positioned between the material and the cylinder.
 5. The apparatus of claim 3 further including a plurality of resilient tines aligned with preselected spaces on the material and having pallet portions thereon for printing the characters upon being struck by said impacting means.
 6. The apparatus of claim 5 wherein the impacting means comprises a plurality of spaced pins arranged in a single turn helix about the cylinder and wherein the pins are sequentially aligned with individual tines as the cylinder rotates.
 7. In an apparatus for printing individual sheets of information wherein the sheets are produced sequentially from the outermost coil of a web of material; an impact mechanism for printing information on the outermost coil of the web; means for continuously urging the web toward the impact mechanism so that the remainder of the web serves as a backing for the outer coil of the web against which the impact mechanism strikes when printing; means independent of the impact mechanism for engaging and holding the outermost coil of the web in a printing plane relative to the impact mechanism and against the web as the outermost coil is printed on; and means for severing sheets from the web.
 8. The apparatus of claim 7 wherein said severing means includes: a pair of rollers between which material from the web advances; means for mounting the rollers to selectively prevent the advancement of the material; and a blade positioned downstream of the rollers to sever a sheet from the material upon engaging the material.
 9. The apparatus of claim 8 wherein the means for mounting the rollers includes pins projecting from each end of each roller wherein the pins engage slots which converge in a direction downstream of the web.
 10. In an apparatus for recording characters selectively and sequentially across an outer coil of material as the material is uncoiled from a web; means for continuously urging the web into a printing plane to position the outer coil for a printing operation; dies for printing the characters on the web; a carrier for moving the dies selectively across and adjacent to the printing plane; a plurality of resilient tines aligned with preselected spaces in the printing plane but positioned on the opposite side of the dies wherein saId tines have portions thereon for striking the dies; a cylindrical helix juxtaposed with and axially extensive across said tines; means for reciprocating said helix normal to its axis to impact said helix against said tines causing said tines to strike said dies and record the characters on the outer coil of the material; means for rotating said helix to position said helix to engage said tines individually and sequentially as said helix is reciprocated; and means for severing the material after the characters have been recorded thereon, wherein the severing means includes means for restraining advancement of the material upon applying a pulling force to the material downstream of the severing means to thereby prevent the force from being transmitted back to the coiled web.
 11. In an impact printer wherein an impactor means comprises a plurality of equally spaced apart and outwardly projecting impacting elements disposed in a single turn helix on the surface of a cylinder rockably mounted for impacting selected ones of a linear array of characters for printing, the improvement comprising: a carrier for the characters mounted for transverse movement relative to and along a line on a web on which printing is to be effected; a plurality of resilient tines having an individual pallet attached to each tine, whereas the pallets are located between the carrier and the cylinder, so that each pallet corresponds to a printing space in a line of print across the web and is sequentially aligned with successive impacting elements as the cylinder rotates for printingly impacting the characters; and magnetic means for rocking the cylinder into element impacting engagement with successive pallets for printing.
 12. A combination according to claim 11 wherein the tines are disposed in parallel relationship, thereby forming a comb; and the magnetic means comprises: a rockable bracket mounted above the comb, the cylinder rotatably mounted in the bracket; and a magnet fixed relative to the comb for selectively attracting the bracket to draw the cylinder toward the pallet. 